RING finger, HC subclass, found in muscle-specific RING finger protein 2 (MuRF-2) and similar proteins
MuRF-2, also known as tripartite motif-containing protein 55 (TRIM55) or RING finger protein 29 (RNF29), is a muscle-specific E3 ubiquitin-protein ligase in ubiquitin-mediated muscle protein turnover and is also a ligand of the transactivation domain of the serum response transcription factor (SRF). It is predominantly slow-fibre associated and highly expressed in embryonic skeletal muscle. MuRF-2 associates transiently with microtubules, myosin, and titin during sarcomere assembly. It has been implicated in microtubule, intermediate filament, and sarcomeric M-line maintenance in striated muscle development, as well as in signaling from the sarcomere to the nucleus. It plays an important role in the earliest stages of skeletal muscle differentiation and myofibrillogenesis. It is developmentally downregulated and is assembled at the M-line region of the sarcomere and with microtubules. MuRF-2 belongs to the C-II subclass of the TRIM (tripartite motif) family of proteins that are defined by their N-terminal RBCC (RING, Bbox, and coiled coil) domains, including three consecutive zinc-binding domains, a C3HC4-type RING-HC finger, Bbox2, and a coiled coil region, as well as a COS (carboxyl-terminal subgroup one signature) box, and an acidic residue-rich (AR) domain. It also harbors a MURF family-specific conserved box (MFC) between its RING-HC finger and Bbox domains.
Comment:C3HC4-type RING-HC finger consensus motif: C-X2-C-X(9-39)-C-X(1-3)-H-X(2-3)-C-X2-C-X(4-48)-C-X2-C, where X is any amino acid and the number of X residues varies in different fingers
Comment:A RING finger typically binds two zinc atoms, with its Cys and/or His side chains in a unique "cross-brace" arrangement.
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